GMRS antenna

[wpwx694]

What's a good antenna for a base station (mobile radio in the house)?

I'm looking at this one

UHF Fiberglass Mobile Radio Antenna,70CM 400-470mhz GMRS Base Antenna 17inch So239 Connector for Ham Radio Device Repeater Mobile Transceiver with Antenna Mount Bracket https://a.co/d/aswvVMe

Or

Sirio CX455 455-470MHz UHF GMRS Base Antenna https://a.co/d/dWNB7ZY

Right now I am using comet cx-333, which I am using for ham also and not getting a good swr for the gmrs side but getting a good swr on the ham side.

Any suggestions?

 

[mmckenna]

Given the choice between those two, I'd absolutely go with the Sirio over the random Cheap Chinese Antenna stuffed in a tube.

The SWR issues is because there's a healthy difference between 440MHz and 462/467 MHz. You either want a dedicated GMRS antenna designed for that band, or you want something that is lower gain/wider bandwidth.

I would not trust the Cheap Chinese Antenna to actually give you 400-470MHz out of a 1/2 wave antenna.

I have a Sirio antenna for an AIS receiver, and it's been a solid performer and stood up well to the weather for almost 10 years now. Bonus points for the N connector, which is what you want over a UHF connector.

 

[wpwx694]

Given the choice between those two, I'd absolutely go with the Sirio over the random Cheap Chinese Antenna stuffed in a tube.

The SWR issues is because there's a healthy difference between 440MHz and 462/467 MHz. You either want a dedicated GMRS antenna designed for that band, or you want something that is lower gain/wider bandwidth.

I would not trust the Cheap Chinese Antenna to actually give you 400-470MHz out of a 1/2 wave antenna.

I have a Sirio antenna for an AIS receiver, and it's been a solid performer and stood up well to the weather for almost 10 years now. Bonus points for the N connector, which is what you want over a UHF connector.

I will have to get this for coax https://a.co/d/a6rIpBU

 

[mmckenna]

Yeah, that's better than nothing. Ideally you'd want the correct connector on the end to match the antenna, but I'd still put the Sirio with an adapter ahead of random Cheap Chinese Antenna.

Just make sure you waterproof all the outdoor connections. The UHF connectors are NOT waterproof. Good N connectors are, but industry standard is still to waterproof all the connections.

 

[smittie]

What about lightning arrestors? I assume they are necessary/required. What is the best location in the system? What should one look for in getting one? What are the less obvious do's and don'ts of properly installing one?

 

[popnokick]

The answers to your lightning, grounding, bonding, and installation questions can be found in this book -
https://www.amazon.com/Grounding-Bo...=1691084959&sprefix=arrl+groun,aps,348&sr=8-1
I cited it from Amazon because you can look inside at the pages. You can also purchase directly from the ARRL bookstore.

 

[mmckenna]

What about lightning arrestors? I assume they are necessary/required.

Yes, by National Electric Code, and thus by your homeowners insurance, as well as good common sense.

What is the best location in the system?

It needs to be installed where the coax enters your home.

What should one look for in getting one?

Polyphaser.

Don't buy cheap random Chinese ones, or no-name ham radio oriented ones. Don't ever skimp on the safety.

What are the less obvious do's and don'ts of properly installing one?

It must be properly grounded to work. You'd be surprised how many of them I see that aren't grounded at all, the person who put them in assumes it's OK and that it'll magically find it's ground path through the radio.

Anything that goes outside the home needs to be properly waterproofed if you want it to last. One wrap of electrical tape is not waterproofing.

 

[smittie]

@mmckenna, thank you.
Grounding, tie it to plumbing or dedicated ground (2 to 3 foot copper rod)?

 

[smittie]

@popnokick, good resource. Reading it now. Thanks.

 

[mmckenna]

Grounding, tie it to plumbing or dedicated ground (2 to 3 foot copper rod)?

Since it's designed to handle nearby lightning strikes that can induce a lot of energy into your antenna/coax, you want it grounded with an 8' long rod.

It's more complex than that, however.
If the coax enters your home near your electric utility entrance, you can ground to the same ground rod that your electrical panel uses. You have to use a new clamp to attach the wire to the existing rod. NEVER disconnect the existing ground wire, ever.

If the coax enters your home more than a few feet away from your electric utility entrance, than you will need to install a new 8 foot long ground rod under your antenna. The antenna mast needs to be grounded to that rod. The lightning arrestor needs to be grounded to that rod. That rod -MUST- be bonded to the homes existing ground rod, as in there needs to be a physical wire running from the new ground rod to the existing one.

This is absolutely the realm of the professional/licensed electrician. Since this can be a life safety thing, you should not rely on some random dude (me) on an internets hobby website for advice. The National Electric Code is very specific and very detailed and using a professional to design/install this is strongly recommended.